The chief executive role is a tough one to fill. From 2000 to 2013, about a quarter of the CEO departures in the Fortune 500 were involuntary, according to the Conference Board. The fallout from these dismissals can be staggering: Forced turnover at the top costs shareholders an estimated $112 billion in lost market value annually, a 2014 PwC study of the world’s 2,500 largest companies showed.